This invention relates to certain triazolopyrimidine compounds, a process for their preparation, compositions containing such compounds, a method for combating a fungus at a locus comprising treating the locus with such compounds and their use as fungicides.
EP-A-0 071 792 claims compounds of the formula in which R1 represents alkyl, halogen, alkoxy, cyano, cycloalkyl, aryl, aryloxy, arylthio, aralkyl, arylthio, arylalkyl, arylalkyloxy or arylalkylthio each optionally substituted by halogen or alkoxy; or (R1)n represents a benzene, indane or tetrahydronaphthalene ring fused with the phenyl ring, aromatic moieties in the above groups being optionally substituted by alkyl, alkoxy, halogen or cyano; n is 1 or 2; R2 and R3 are each hydrogen, alkyl or aryl, A represents a nitrogen atom or a CR4 group, and R4 is as R2 but can also be halogen, cyano or alkoxycarbonyl or together with R3 can form an alkylene chain containing up to two double bonds. The compounds are said to be active against various phytopathogenic fungi, especially those of the phycomycete class. However evidence of fungicidal activity is only provided for these compounds against Plasmopara viticola, a member of the oomycete class of fungi. EP 0 550 113-A2 claims compounds of the formula in which R1 represents an optionally substituted alkyl, alkenyl, alkadienyl, cycloalkyl, bicycloalkyl or heterocyclyl group; R2 represents a hydrogen atom or an alkyl group; or R1 and R2 together with the interjacent nitrogen atom represent an optionally substituted heterocyclic ring; R3 represents an optionally substituted aryl group; and R4 represents a hydrogen or halogen atom or a group —NR5R6 l where R5 represents a hydrogen atom or an amino, alkyl, cycloalkyl or bicycloalkyl group and R6 represents a hydrogen atom or an alkyl group. Thus, compounds in which R1 is a trifluoromethylalkyl group are generally embraced by this patent application. However, there is no single compound disclosed in which R1 is a trifluoromethylalkyl group.